[KAFKA-10239] The groupInstanceId field in DescribeGroup response should be ignorable

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.5.0, 2.4.1
• Fix Version/s: 2.6.0, 2.4.2, 2.5.1
• Assignee: Boyang Chen
• Reporter: Jason Gustafson
• Created: 06/Jul/20 19:53
• Updated: 07/Jul/20 03:35
• Resolved: 07/Jul/20 03:35

Description

We noticed the following error in the logs in the handling of a DescribeGroup request:
```
org.apache.kafka.common.errors.UnsupportedVersionException: Attempted to write a non-default groupInstanceId at version 3
```
The problem is that the field is not marked as ignorable. So if the user is relying on static membership and uses an older AdminClient, they will see this error.

Issue Links

• links to: GitHub Pull Request #8989